There’s little, if any, argument that lead-based paints in homes can be toxic, particularly to young children, who are susceptible to brain damage or learning disabilities if they ingest it. And tons of it — literally — are out there: The Environmental Protection Agency estimates lead was used in paint in more than 38 million homes before it was banned for residential use in 1978.

As of April, if you renovate a home that was built before 1978, potentially sending the paint’s potent substance into the air, your contractor will have to prove that he’s able to get the lead out.